In the first moments after Sarah Palin was selected as John McCain's running mate, an aide to Barack Obama fired off a highly critical e-mail to reporters denouncing the Republican candidate's selection of a former small town mayor to be a heartbeat away from the presidency. It backfired. Since then, Barack Obama' s campaign has employed a strict policy -- don't publicly go after Sarah Palin. At first, it was because they worried about appearing sexist and out-of-touch with middle America. Then when Palin was struggling in media interviews, Obama's felt she was doing enough harm to herself. But now,...